Regulating electric motors.



No. 635,139. Patented Oct. 17, I899. M, T. A. KUBIERSCHKY.

REGULATING ELECTRIC MOTORS.

(Application filed Aug. 4, 1899.)

(Nb Model.) 3 Sheets-Sheet I.

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Patented Oct. l7, I899. M. T. A. KUBIERSGHKY.

REGULATING ELECTRIC MOTORS.

(Application filed Aug. 4, 1899.)

3 Sheets-Sheet 2;

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No. 635,|39. Patented Oct. I7, I899.

M. T. A. KUBIERSCHKY. I

REGULATING ELECTRIC MOTORS.

(Application filed Aug. 4, 1899.) (No Model.) 3 Sheets-Sheet 3Witnesses. S lnvenbor. 6w MarbinTJQKubierschky.

. bywgggj UNITED STATES PATENT @rrrcn.

MARTIN T. A. K'UBIERSCHKY, OF BERLIN, GERMANY.

REGULATING ELECTRIC MQTQRS.

SPECIFICATION forming part of Letters Patent No. 635,139, dated October17, 1899.

Application filed August 4, 1899. Serial No. 726.144. (No model.)

To all whom it may conccrm Be it known that I, MARTIN 'l. A. KUBIER-SOHKY, a subject of the Emperor of Germany, residing at Berlin, Germany,have invented certain new and useful Improvements in Regulating ElectricMotors, (Case No. 924,) of which the following is a specification.

The series motors which are at present almost universally used forstreet-railway traction have two defects. In the first place whenstarting the cars a great deal of electrical energy is always destroyedby the resistance, and in the second place mechanical energy isdestroyed by the useless working of the brake when braking on levelroads or on descending grades. The losses caused by the resistances werepartially prevented or at least lessened during the first few years ofstreetrailway work by the series-parallel method of control. The largebraking losses, compared with the total power consumption, have,however, lately caused engineers to give this subject more seriousattention and have led to a number of proposals more or less worthy ofnotice. The simple conversion of the shuntmotor into. a dynamo thereforeleads to its use on street-railways, and the shunt-motor has really inisolated cases been employed for high-grade railways. The disadvantagesof using a shunt motor alone were, however, soon recognized, and thesimultaneous use of transportable secondary batteries having in themeantime become more general endeavors were made to secure all theadvantages of the shunt-motor without having its disadvantages byseparately exciting the fieldwinding with a small secondary battery andnot from the line-voltage. A really profitable recovery of the momentumof the cars is, however, only partially obtained by the methodsnowknown, because with the aid of these methods of control on descendinggrades a considerable portion of the work consumed in elevating may beregained, whereas on stopping very little energy indeed is recovered.The terminal voltage of the armature of a shunt or separately-exciteddynamo at constant field excitation being directly proportional to thenumber of turns, the voltage when braking or lowering the speed canonly, therefore, be kept higher than the line-voltage by intensifyingthe field.

This field in tensity, however, without taking into consideration themeans available for producing it, soon attains in practice a certainlimit, so that when stopping nothing more can be done after the slowestspeed is attained than to brake off the remainder of the kinetic energy.The method described below aims at the removal of this disadvantage andat the same time is intended to prevent to a great extent the losses dueto the starting resistances. The fundamental idea of this method is toat first feed the armature of the motor when starting with lowelectromotive force and to gradually increase the latter until itbecomes equal to the line-voltage. IVhen stopping, the electromotiveforce counteracting the armature-voltage is then gradually lessened, andthus enables the armature to produce energy until just before stopping.In order to put this idea into practice, a secondary battery isnecessary, which is frequently employed in mixed systems of traction andcan also be used with advantage on elevated and ordinary railways.

In the following description it is assumed, for the sake of exampleonly, that the battery is divided into five groups. The battery can,however, be of course subdivided into any number of groups, according torequirements.

Figures 1 to 6, inclusive, represent connections corresponding todifferent controller positions. Fig. 7 shows a development of the maincontroller-cylinder and of the batteryswitch, together with theconnections cooperati'ng therewith; and Figs. 8 and 9 arerepresentations in elevation and plan, respectively, of a device forgiving step-by-step movement to the battery-switch.

Before proceeding to a detailed explanation of the controller and itsconnections a brief description of the combinations of circuits shown inFigs. 1 to 6, inclusive, will be useful. TVhen the controller is at itsoff position, the groups of batteries shown are connected in seriesbetween trolley and ground and are thus being charged. At the firstcontroller position (indicated in Fig. 1) the armature of the motor isclosed upon the resistances r 0', while its field is connected acrossone of the groups of batteries. This connec tion represents the brakingconnection for the motor when it is being brought to rest,

but has no function when the motor is being started. As thecontroller-switch is turned the resistance is cut out and the armatureconnected in shunt to the field. This represents the first runningposition of the controller. A further movement of the controller causesthe free end of the resistance (indicated in Fig. 2) to be connectedacross an adjacent group of battery-cells, this connection being atransition stop to the subsequent position, (represented in Fig. 4G,) inwhich the armature, with the resistance in series, is connected acrosstwo groups of battery-cells, while the field remains connected, asbefore. The next step consists in cutting out the resistance, asindicated in Fig. 5, while the subsequent steps are repetitions of theforegoing ones until the final position of the controllercylinder isreached, when, as shown in Fig. 6, the armature is connected directlybetween trolley and ground and receives the full-line potential. Inbringing the motor to rest the same operations are gone through with,but in the reverse order. When on downgrades or under otherconditionswhich cause the motor to act as a generator, it will be observed that byreason of the connections thus made possible the potential opposed tothat generated by the motor may always be rendered such as to cause themotor to feed back current through the storage batteries to line. Withthis arrangement, however, it will be noted that from the time the motoris started from rest until the time when the controller is brought backto its off position the field of the motor is being continually excitedby the same group of storage cells, thus causing a considerableinequality between the charging and discharging of that group and of theremaining groups. To obviate this objection, I make use of abattery-switch, the function of which is to cause the different groupsof cells to be used in rotation to excite the motor-field, the changesand connections being effected each time the controller is brought backto its off position.

In Fig. 7 the battery-switch is shown at the right, while the maincontroller switch is shown at the left, both switches being indicated bya diagrammatic development of their contacts and contact-fingers. Forconvenience the contact-fingers cooperating with the battery switch areshown as disconnected therefrom; butin practice the fingers will al waysrest upon some one of the vertical sets of contacts through which thedotted lines it ij k Zare passed. These vertically-arranged contacts arecross-connected, as indicated, with leads brought out and connected withtwo sets of rings-three each in number'from which sliding connectionslead to contact-fingers 'on the main controller. Connections from thebattery lead to contact-fingers which cooperate with thevertically-arranged contacts of the battery switch.

Supposing now the development of the main cylinder to be slid from rightto left under the row of contact-fingers, it can be easily seen that theconnections shown in Figs. 1 to '0 will be made one after another intheir turnthat is, the field will be almost constantly excited by onebattery group,while the armature is connected in series successivelywith one, two, three, and four groups and finally receives theline-voltage direct. At this position (VI) of the controller the car attains its greatest speed, which speed can still be increased byweakening the fieldexeitation with resistances. This weakening of thefield-excitation is not shown in the drawings, as it has really nothingto do with the invention, the process being well known.

As now the magnet-field of the motor is constantly excited at everyrunning position of the controller, while the armature at the same timeworks against an eleetromotive force which is different for each pointof the controller, every running position of the controller reallycorresponds to a certain speed, and it is not necessary when running atlow speed to introduce resistances, as was the case in all formersystems. in order to reduce the speed thus obtained or to stop the carwith the system proposed here, all that has to be done is to slowly turnback the controllerhandle toward 0, which causes the electrovoltageavailable for any one of the driving points, and consequently to produceenergy for the charging of the battery or to give off current to themain conductor (on simultaneously braking the car) in proportion to theintensity of current delivered. In this manner power is regained fromthe energyin the car until (at controller position H) the slowest speedis attained. in order now to stop the car, position I is used, in which,as shown in Fig. l, the armature is short-circuited over a resistance,the field remaining excited as before. In this position, therefore, noenergy is regained; but there is, however, very little less, as only avery small quantity of the ki netic energy which is left is destroyed inthis manner.

In employing the above-mentioned connection the different groups ofaccumulators work unequally at slow speeds and also when starting, andthis inequality is only partially counterbalanced by the charge theyreceive when braking. In order to compensate for this inequality, thebattery-switch described above is so coupled with the driving andbraking cylinder that when the latter is turned from position I to oilthe formeris automatically shifted forward a fifth of its wholecircumference every time. Any me chanical method of a kinetical naturemay be employed to attain this end, one of these methods being shown inFi s. 8 and 9.

The spindle of the main. controller carries two cams K, which cooperate,respectively,

crank lever suitably pivoted to a part of the controller-casing by meansof a shaft P, to

motive force of the armature to exceed the with rollers affixed to thearms A Aof a bellwhich is attached a lever L. The battery switch islocated adjacent to the main controller-switch, and upon its shaftcarries a loosely-mounted plate 0, provided with a slot (indicated at Q)and having apawl R pivoted to its upper side. A pin S, secured to theend of the lever L, cooperates with the sides of the slot Q and servesto partially rotate the plate 0 as the lever L is moved aboutits shaftP. A ratchet T is fixed to the shaft of the battery-switch and isoperated upon by the ratchet R, the free end of which is suitablyspring-pressed against the teeth of the ratchet. The parts are soorganized and correlated that as the main controller-shaft is moved fromits zero or off position the arm L is moved toward the right, so as tocause the pawl R to slip over one of the teeth of the ratchet-wheel T.The main controller maythen be turned to its final position withoutproducing any further motion of the lever-arms and ratchet. When,however, the main controller is turned back to its off position thereverse operation takes place, thus causing the battery-switch to berotated through a limited arc corresponding in this particular instanceto onefifth of its circumference, thus causing the contact-fingers ofthe battery-switch to move from one set of contacts to the set nextsucceeding.

The connections diagrammatically shown permit only one direction forrunning the motor, so that in order to obtain motion in the oppositedirection I provide a reversingswitch, (indicated at X,) the characterof which will be readily understood by those skilled in the art withoutfurther explanation.

What I claim as new, and desire to secure by Letters Patent of theUnited States, is

1. The combination of a circuit of substantially constant potential, twosources of current of inversely-variable electromotive force, means forcombining said electromotive forces, and means for impressing theresultant electromotive force on said circuit.

2. The combination of a momentum-driven generator, a separate source ofelectromotive force, means for combining said electromotive force withthat of the generator, and means for varying said electromotive force.

3. The combination of a momentum-driven generator, a source ofelectromotive force in series with the generator and variable i11-versely with the electromotive force of the generator, and a circuitacross which the gen erator and said source of electromotive force areconnected.

at. The combination of a generator of varying electromotive force,storage batteries in series therewith, a constant-potential circuitacross which the generator and storage batteries are connected and meansfor varying the number of cells of battery at will.

The combination of a generator of vary ing electromotive force, astorage battery in series therewith and means for varying theclectroinot-ive force of the battery inversely with that of thegenerator.

(3. The combination of a dynamoelectric machine, a storage batterycomprising groups of cells, mains between which the battery isconnected,electricalconnectionsbetween said machine and one or more ofsaid groups and a switch for shifting said electrical connections toanother group or groups of cells.

'7. The combination of a dynamo-electric machine, a storage batterycombining groups of cells, constant-potential mains between which thebattery is connected, electrical connections between the field of saidmachine and one of said groups of cells and means for changing theconnections of the battery from one group of cells to another.

8. The combination of a dynamo-electric machine, a storage batterycomprising groups of cells, mains between which the battery isconnected, electrical connections between the field of said machine andone of said groups, and a controlling-switch for changing the c011-nections of one group of cells to another when the controlling-switch isturned to its off position.

9. The combination of a constant-potential circuit, a storage batteryconnected across said circuit, and a dynamo-electric machine having itsfield and armature arranged to be separately connected across differentnumbers of cells of said battery.

In witness whereof I have hereunto set my hand this 17th day of June,1899.

MARTIN T. A. KUBIERSOHKY.

Witnesses:

WALDEMAR IIAUPT, HENRY HASPER.

